PTL1, PTL2 and PTL3 disclose a heat exchanger. These heat exchangers have a tank portion. The tank portion is formed of a core plate and a tank member. The tank member and the core plate are connected to each other by a clamping section. The clamping section is provided with an edge of the tank member and an edge of the core plate. The edge of the core plate is subjected to deformation processing so as to wrap an edge of a housing. On the edge of the core plate, a bendable section called a claw is provided. On the edge of the tank member, a step difference portion that receives the claw is provided. The claw is bent to hold the edge of the tank member.